Any auto A/C gurus on here?

[FMCoug]

The A/C on my van quit this week. Was fine and then just started blowing warm air. Compressor wasn't engaging at all so I suspected a low charge. Jumpered the low pressure switch and the compressor works fine. Checked low side pressure and it was a big goose egg. Put about half a can of refrigerant in (had it around) and got it about to about 25 psi ... still not enough to blow cold. Ran it for about 15 minutes ... pressure still 25 psi. Shut off the van, went to the store to get more refrigerant, when I got back it was down to 15 psi. Also, after putting refrigerant in, with the van off, you can hear a hissing. So I'm pretty sure there is a pretty bad leak somewhere. One thing I am trying ... it seems like the Shraeder valve where you add refrigerant could be a likely spot for a leak ... so I lefte the pressure guage on it overnight so it would be engaged.

Any suggestions on further troubleshooting? Wish I had some real manifold guages and a vacuum pump ...

[BlueHair]

The A/C on my van quit this week. Was fine and then just started blowing warm air. Compressor wasn't engaging at all so I suspected a low charge. Jumpered the low pressure switch and the compressor works fine. Checked low side pressure and it was a big goose egg. Put about half a can of refrigerant in (had it around) and got it about to about 25 psi ... still not enough to blow cold. Ran it for about 15 minutes ... pressure still 25 psi. Shut off the van, went to the store to get more refrigerant, when I got back it was down to 15 psi. Also, after putting refrigerant in, with the van off, you can hear a hissing. So I'm pretty sure there is a pretty bad leak somewhere. One thing I am trying ... it seems like the Shraeder valve where you add refrigerant could be a likely spot for a leak ... so I lefte the pressure guage on it overnight so it would be engaged.

Any suggestions on further troubleshooting? Wish I had some real manifold guages and a vacuum pump ...

I suggest taking it to a mechanic. It's been a few years, but it seems like they only charged my around $50 to fix the leak in my AC.

[FMCoug]

I suggest taking it to a mechanic. It's been a few years, but it seems like they only charged my around $50 to fix the leak in my AC.

But where's the fun in that? Seriously, that sounds really cheap to me. Do you happen to remember where you took it?

[Shaka]

I had two leaks in my Saab's AC. One was the Shrader Valve and the other was one of the lines. You're barking up the right tree.

[FN Phat]

The A/C on my van quit this week. Was fine and then just started blowing warm air. Compressor wasn't engaging at all so I suspected a low charge. Jumpered the low pressure switch and the compressor works fine. Checked low side pressure and it was a big goose egg. Put about half a can of refrigerant in (had it around) and got it about to about 25 psi ... still not enough to blow cold. Ran it for about 15 minutes ... pressure still 25 psi. Shut off the van, went to the store to get more refrigerant, when I got back it was down to 15 psi. Also, after putting refrigerant in, with the van off, you can hear a hissing. So I'm pretty sure there is a pretty bad leak somewhere. One thing I am trying ... it seems like the Shraeder valve where you add refrigerant could be a likely spot for a leak ... so I lefte the pressure guage on it overnight so it would be engaged.

Any suggestions on further troubleshooting? Wish I had some real manifold guages and a vacuum pump ...

From the sounds of it, you have done about all a backyard knuckle buster can do in his own garage. Time to call in the experts.

[BlueHair]

But where's the fun in that? Seriously, that sounds really cheap to me. Do you happen to remember where you took it?

It was a little place in Provo by Deseret Industries. I can't remember the name of it. Right at the bottom of the hill on the east side of the road.

[FMCoug]

From the sounds of it, you have done about all a backyard knuckle buster can do in his own garage. Time to call in the experts.

So I called around and talked to a few places. Based on what I told them I had already done, they said it would be hourly at this point at anywhere from $65 to $79 / hr. Said it could be inside the evaporator core or its housing, evaporator tube, etc. Give that this is an old van, I'm not going there. They did say if I find it and fix it, they will pull vaccuum, leak test, and recharge for around $100.

So I decided to add auto A/C to my bag of tricks and tear it apart myself. I have a GM Service Manual so I have all the info I need.

[FN Phat]

So I called around and talked to a few places. Based on what I told them I had already done, they said it would be hourly at this point at anywhere from $65 to $79 / hr. Said it could be inside the evaporator core or its housing, evaporator tube, etc. Give that this is an old van, I'm not going there. They did say if I find it and fix it, they will pull vaccuum, leak test, and recharge for around $100.

So I decided to add auto A/C to my bag of tricks and tear it apart myself. I have a GM Service Manual so I have all the info I need.

Right on! That should be a good project to tackle.

[FMCoug]

So the plot thickens. Since this is a van, everything is of course hard to get to. Had to remove the air cleaner, coolant overflow tank and battery to even get to the A/C components. Pulled the accumulator and evaporator (which involved removing the blower motor and a bunch of other stuff around it as well) and everything looks great. No dye showing up anywhere. Hoses, evap tube, evap, accumulator, etc.

Then I notice the evaporator tube has branch heading towards the rear of the van. Since it's a conversion van, the normal "rear air" controls have been removed and there is a switch labeled "fan" in the overhead along with all the lighting controls etc. tha turns on the rear fan to circulate air through all the ducts plumbed into the conversion stuff. So we had just assumed it was only a fan ... not air. Anyway, I start tracing this (had to take off the engine cowl inside the van to see the back of the compressor, etc.) and ultimately take out a bunch of the wood trim, paneling, etc. in the very back to get the trim piece off where the rear fan is. Low and behold, there is an evaporator back there ... hmmm. Makes me wonder if it was blocked to the back somehow and that broke loose which is why it won't hold pressure now but was working in just the front for a while.

Next step is to jack it up so I can trace the hoses from the evaporator in the back up to the front. According to the GM service manual, they run along the frame. But the conversion thing means anything goes as the conversion company woudl have run whatever they wanted ... those hoses appear to go through the sidewall behind the paneling, etc.

Good times.

[FMCoug]

The good news? I now have all the tool and know how to do 90% of what I'd ever need to with auto A/C. The bad news? I need a new compressor.